Many countries now or may soon require that photovoltaic (PV) arrays used as electric generation facilities stay connected with the electric grid when the grid is in fault. Remaining connected during a fault (also referred to as a transient, such as a low voltage ride through (LVRT) or zero voltage ride through (ZVRT)) can be challenging from an engineering perspective.
Conventional DC/AC systems, which convert DC from the array to AC for the grid, are subject to damage if an array remains connected to the grid during a LVRT or ZVRT due to overvoltage in a DC link of the DC/AC system. A PV-side converter will pump energy in to the DC link while grid-side will have reverse power from the grid due to the large transient.
Accordingly, a new system and method are needed for a PV array to remain connected to an electricity grid during a transient without suffering damage.